total and absolute destructiveness, especially toward the world at large and including oneself:

the power-mad nihilism that marked Hitler's last years.

4.

Philosophy.

an extreme form of skepticism: the denial of all real existence or the possibility of an objective basis for truth.

nothingness or nonexistence.

5.

(sometimes initial capital letter) the principles of a Russian revolutionary group, active in the latter half of the 19th century, holding that existing social and political institutions must be destroyed in order to clear the way for a new state of society and employing extreme measures, including terrorism and assassination.

6.

annihilation of the self, or the individual consciousness, especially as an aspect of mystical experience.

1836 in the religious or philosophical sense, from French nihiliste, from Latin nihil (see nihilism). In the Russian political sense, it is recorded from 1871. Related: Nihilistic.

nihilism

n.

1817, "the doctrine of negation" (in reference to religion or morals), from German Nihilismus, from Latin nihil "nothing at all" (see nil), coined by German philosopher Friedrich Heinrich Jacobi (1743-1819). In philosophy, an extreme form of skepticism (1836). The political sense was first used by German journalist Joseph von Görres (1776-1848). Turgenev used the Russian form of the word (nigilizm) in "Fathers and Children" (1862) and claimed to have invented it. With a capital N-, it refers to the Russian revolutionary anarchism of the period 1860-1917, supposedly so called because "nothing" that then existed found favor in their eyes.

An approach to philosophy that holds that human life is meaningless and that all religions, laws, moral codes, and political systems are thoroughly empty and false. The term is from the Latinnihil, meaning “nothing.”